Process for making and composition of low viscosity coal-water slurries

Abstract

A coal-water slurry having a high solids content and improved pumpability containing a viscosity improving amine additive from the group consisting of substituted 3-amino carboxylic acids, dialkanol alkyl amines or diamines is provided as well as a method of preparation.

We claim: 
     
       1. An aqueous slurry of a comminuted solid fuel having improved pumpability properties which comprises from about 50 to 70 weight percent of an 8 to 200 mesh comminuted fuel, from about 50 to 30 weight percent water and from about 0.01 to 5 weight percent of a compound selected from the group consisting of: (a) a beta substituted carboxylic acid represented by the formula: ##STR2##  wherein R 1  and R 2  each represent hydrogen or a hydrocarbon radical containing from 1 to 20 carbon atoms provided that R 1  and R 2  together contain no more than 20 carbon atoms:   (b) a dialkanol alkyl amine represented by the formula   (HO--CH.sub.2 --CH.sub.2).sub.2 =N--R.sub.3        wherein R 3  is hydrogen or a hydrocarbon chain having from 1 to 20 carbon atoms; and   (c) a diamine represented by the formula   NH.sub.2 --R.sub.4 --NR.sub.5 R.sub.6        wherein R 4  is a divalent hydrocarbon radical having from 2 to 20 carbon atoms and R 5  and R 6  each represent a hydrocarbon radical having from 2 to 20 carbon atoms with the proviso that the sum of the carbon atoms in R 4 , R 5  and R 6  does not exceed 24.   
     
     
       2. The process of claim 1 in which the solid fuel is a coal selected from the group consisting of lignite, sub-bituminous, bituminous and anthracite coals. 
     
     
       3. The process of claim 1 in which the selected compound is added in an amount between about 0.2 and about 3.0 wt. %. 
     
     
       4. The process of claim 1 in which at least 50% of the solid fuel passes through a 200 mesh sieve. 
     
     
       5. The process of claim 1 in which at least 80% of the solid fuel passes through a 200 mesh sieve. 
     
     
       6. The process of claim 1 in which all of the solid fuel passes through a 60 mesh sieve. 
     
     
       7. The process of claim 1 in which the slurry contains between about 50 and about 60 wt. % solid fuel measured on a dry basis. 
     
     
       8. A process for making the pumpable comminuted solid fuel-water slurry of claim 1 which comprises adding from about 0.01 to about 5.0 weight percent of a member of said group of compounds based on the resulting solid fuel-water slurry as a whole to solid carbonaceous fuel prior to or simultaneously with addition of a minor portion of water; comminuting said solid fuel to the extent that all of it passes through a sieve no more coarse than 60 mesh and adding a major portion of water to said comminuted solid carbonaceous fuel and compound in sufficient amount to comprise in toto from about 30 to about 50 weight percent of the resulting solid fuel-water slurry as a whole. 
     
     
       9. An aqueous slurry of a comminuted solid fuel having improved pumpability properties which comprises from about 50 to about 70 weight percent of an 8 to 200 mesh comminuted fuel, from about 50 to 30 weight percent water and from about 0.01 to 5 weight percent of a compound selected from the group consisting of: ##STR3## wherein R 7  is a hydrocarbon chain containing from 10 to 18 carbon atoms,   (HO--CH.sub.2 --CH.sub.2).sub.2 ═NR.sub.8              (b)     wherein R 8  is a hydrocarbon chain containing from 10 to 20 carbon atoms,     NH.sub.2 --CH.sub.2 --CH.sub.2 --CH.sub.2 --N═(CH.sub.2 --CH.sub.3).sub.2                                         (c)     and     NH.sub.2 --CH.sub.2 --CH.sub.2 --NH.sub.2                  (d)     
     
     
       10. The process of claim 9 in which the solid fuel is a coal selected from the group consisting of lignite, sub-bituminous, bituminous and anthracite coals. 
     
     
       11. The process of claim 9 in which the selected compound is added in an amount between about 0.2 and about 3.0 wt. %. 
     
     
       12. The process of claim 9 in which at least 50% of the solid fuel passes through a 200 mesh sieve. 
     
     
       13. The process of claim 12 in which at least 80% of the solid fuel passes through a 200 mesh sieve. 
     
     
       14. The process of claim 9 in which all of the solid fuel passes through a 60 mesh sieve. 
     
     
       15. The process of claim 9 in which the slurry contains between about 50 and about 60 wt. % solid fuel measured on a dry basis. 
     
     
       16. A process for making the pumpable comminuted solid fuel-water slurry of claim 9 which comprises adding from about 0.01 to about 5.0 weight percent of a member of said group of compounds based on the resulting solid fuel-water slurry as a whole to solid carbonaceous fuel prior to or simultaneously with addition of a minor portion of water; comminuting said solid fuel to the extent that all of it passes through a sieve no more coarse than 60 mesh and adding a major portion of water to said comminuted solid carbonaceous fuel and compound in sufficient amount to comprise in toto from about 30 to about 50 weight percent of the resulting solid fuel-water slurry as a whole.